The Tier-1 <video>s now carry native controls; update the shared CSS comment
to match (CodeRabbit).

- generate_animations: fail fast with a clear message when ffmpeg is absent
(Gemini).
- Schroeder _fit: guard against fewer than two points in a T20/T30 range and
a non-decaying slope, and keep xmax robust when a fit is unavailable
(Copilot).
- Site <video>s: add native `controls` (a keyboard-accessible pause/stop for
the looping motion, WCAG 2.2.2) and move the description to `title`, dropping
the `role="img"`/`aria-label` pair so the controls stay exposed to assistive
tech (CodeRabbit).
- Spanish: "energy sloshes" -> "la energía va y viene" (technical register;
ES intensity clips regenerated) (CodeRabbit).
- Group `no-autoplay` with the other `no-*` html-validate rules (CodeRabbit).

Add the four Tier-1 animation clips the audit prioritised — level-vs-time
phenomena the library already computes, rendered deterministically by
generate_graphs.py:

- time-weighting ballistics: the Fast/Slow/Impulse detectors chasing a tone
burst, Impulse decaying slowest (IEC 61672-1);
- onset detection: an L_AF history with the >10 dB/s onset highlighted and
OR/LD/P/KI shown live (NT ACOU 112);
- instantaneous intensity: p·u flowing for a progressive wave vs sloshing
about zero for a standing wave (IEC 61043);
- Schroeder backward integration: the decay curve emerging from the tail,
ending with the T20/T30 lines (ISO 3382).

Each is produced in the four language x theme variants as a compact WebM for
the site (embedded as an autoplaying, looping <video>) and, for English, an
animated GIF for the GitHub docs. A new `_translate_str` localises the
per-frame labels (the clips never pass through themed_path), the site gains
<video> theme-switching CSS, and `make animations` (kept out of CI, since
video is not byte-reproducible) regenerates them.

* Audit pass 11a: seven new documentation diagrams

Add SVG flow diagrams for the seven topics the audit flagged as having no
schematic: the exponential-detector chain of the time weightings
(IEC 61672-1), stateful vs reset block processing, the multichannel
array-shape flow, the open-plan spatial-decay line (ISO 3382-3), the
ISO 12999-1 uncertainty pipeline, the ISO 11654 absorption-rating flow and
the Zwicker loudness-model chain (ISO 532-1).

Each is generated deterministically by generate_diagrams.py in the four
EN/ES x light/dark variants, with every Spanish label added to the _ES
table (decimals localised to commas), and embedded in the repo docs and
both site trees beside the existing worked-example plots.

* Fix ISO 532-1 table citations in the Zwicker diagram

Review of the diagram against loudness_zwicker.py found two mislabelled
tables: the equal-loudness correction and lower-critical-band grouping is
Table A.3 (not A.4), and the threshold in quiet LTQ is Table A.6 (not A.3).
Reassign the a0/DDF/LTQ corrections to the core-loudness step (Tables
A.4-A.7) where they belong, update the Spanish labels, and align the ES
psychoacoustics alt text with the guide's own term "sonos" (was "sonios").

* feat: complete the .plot() convention and tidy the plotting layer

Audit batch 10:

Every result dataclass with a plottable series now exposes .plot()
(eleven new): open-plan spatial decay with the Clause 6.2 regression
and rD/rP markers; outdoor attenuation with signed pos/neg stacking (a
net ground gain stacks below zero); impedance-tube alpha(f) with the
muted |r| companion; Monte Carlo histogram with the coverage interval -
via a new opt-in monte_carlo(keep_samples=True) that stores the sample
on the result (the 8 MB/1M-trial cost stays off the default path, and
.plot() without samples raises with the hint); occupational-exposure
per-task contributions with the LEX and LEX+U lines; plus simple
renderers for static airflow, airborne/impact prediction,
airborne/impact insulation bands and band uncertainty. TransferMatrix
and ScatteringUncertainty are documented skips (value objects with no
stored frequency axis). The five priority plots are mentioned in their
guides on all three surfaces.

Plotting hygiene: _freq_axis in the enclosed-space renderer (minor-tick
suppression restored); shared _band_axis/_fractile_band/_hatch_invalid
helpers and plot_weighted_absorption folded into _plot_rating; named
color constants with the three neutral greys collapsed into one _C_MUTED
(the per-metric tonality red and roughness brown stay, commented);
every title now leads with its standard designation (17 aligned, with
per-type designations where one renderer serves several standards);
band x-labels unified to the dominant wording; the 11 result: Any
renderers typed; kwargs documented; the missing small legend fixed;
user color propagates into the companion fill_between in the five
loudness/tonality/roughness renderers.

Tests: 11 new kwargs-forwarding cases, 13 content/raise tests, and the
external-ax contract extended to all single-axes results (64/64).

* fix: address the review findings on the plotting batch

- plot_monte_carlo lets callers override density (setdefault instead of
a hardcoded kwarg that collided) (Copilot)
- plot_open_plan imports matplotlib.ticker after the lazy axes creation
so a missing matplotlib still raises the actionable hint (Copilot)
- the exposure plot computes its y-limits from the data instead of
clamping at 0 dB (negative levels no longer clip) (Copilot)
- the sound-power legend also renders when the caller passes label=
(Gemini)
- the insulation plot annotations are quoted for consistency (the file
already had future annotations, so this is style, not a crash fix)
(Gemini)
- the GUM example comment now says honestly that the committed figure
overlays the Gaussian, and the open-plan one-liner snippet gains
plt.show(), on all surfaces (CodeRabbit)

* test: the tests batch of the audit

Audit batch 9 - the test layer hardens, with src/ numerics untouched:

reference_data drift closure: the test files that duplicated oracle
values as literals now import the shared constants (11 files), with a
rewritten module docstring describing the actual regime; the EN 12354-6
Annex E surfaces move into reference_data (test + conformance import
them); all 8 previously-dead constants are wired into asserts instead
of deleted.

Conformance: 90 -> 95 checks across 22 domains, all passing and
byte-stable. New: ECMA-418-1 critical-band and proximity anchors (new
Prominent discrete tones domain), an ISO 10534-2 synthesize->recover
identity, the ISO 717-2 Annex C.1 impact rating, and an ISO 18233 sweep
deconvolution vs freqz check - each with a tolerance-rationale comment
(new convention). The STI domain is now Speech transmission
(IEC 60268-16), the ISO 9613-1 checks live under outdoor propagation,
and the registry floors are realistic.

match= backfill: 98 bare pytest.raises(ValueError) sites now pin the
actual message; one test found passing via the wrong validation path is
fixed to exercise the intended error.

Performance: the eight heavy files drop from 203 s to 148 s and the
full suite from ~360 s to 288 s (1785 tests) - module-scoped STIPA
fixture, shortened property-test signals with measured-margin comments
(exact anchors kept at the length their tolerance needs, with the
measurements documented), and the zero-margin cached<uncached
performance assert gains a 1.5x margin (it flaked on CI by 0.06 ms).

Small gaps: 13 zips gain strict=True and 3 become itertools.pairwise;
StatefulWeightingFilter gains its three missing invalid-input tests;
utils.py verified as having no raising paths.

* test: show both chained values in the ISO 10534-1 check display

A |r| mismatch used to fail the check while displaying only matching
absorption values; the expected/computed strings now carry both, like
the ECMA-418-1 check does (CodeRabbit).

* test: escape the pipes in the ISO 10534-1 display strings

Unescaped | inside GFM table cells broke the CONFORMANCE.md rendering
(CodeRabbit); regenerated byte-stable.

* docs: traceability fixes and the target taxonomy

Approved conclusions of the standards-traceability report:

Traceability (P1):
- the room-acoustics footer claimed ISO 3382-3:2022 while the code
implements and verifies :2012 - the footer now tells the truth
- CONFORMANCE.md becomes visible: a Reference page on the site (EN/ES)
explains the report and links the generated table (copying 300
auto-generated lines would drift), docs/README.md indexes it, and
why-phonometry links it after its comparison table
- nine citation patches with honest scoping: the ISO 1996-2 facade
claim reworded as measurement context; ECMA-74 out of the
tone-prominence footer (context note added); ISO 9613-1 declared in
surface-scattering with clause delimitation; materials cites the
BS EN ISO 10534:2001 editions the code cites; the EN 12354 typo;
ISO 266 and ISO 5725 added with narrow scope; IEC 61252 designations
unified
- class_limits exported (it was public-but-unimportable), documented in
the API reference and surfaced in filter-banks section 6

Taxonomy (approved target, sidebar moves only - zero URL changes):
- renamed: Signal processing & filters
- new groups: Instrumentation, calibration & compliance; Materials &
surfaces
- Perception & speech splits into Psychoacoustics (+tone-prominence),
Speech & intelligibility, and Hearing & occupational exposure
(+occupational-exposure)
- docs/README.md mirrors the new order; Conformance joins Reference

* docs: terminology polish on the new conformance pages

key differentiator (not 'differential asset'), governing band/frequency
(not 'binding'), pasa/no pasa, expresiones en forma cerrada, 'en la que
se basan las etiquetas nominales', and air-attenuation relations in
both languages (Gemini)

* docs: retrofit the house conventions onto the legacy guides

Audit batch 8 - the pre-convention guides catch up with the style the
newer ones follow, on all three surfaces (repo, site EN, site ES):

- Standards footers for the ten guides that cited clauses inline but
never closed with the normative scope (calibration, filter-banks,
intensity, levels, time-weighting, weighting, outdoor-propagation,
sound-power, psychoacoustics, plus materials synced from the site
style and a new room-acoustics footer); block-processing,
multichannel and getting-started verified as having no normative
citations to footer
- every touched snippet is now self-contained or carries an explicit
reuse annotation, and ~20 prints gained expected outputs EXECUTED
against the library (levels LN values re-verified, materials
# 222956, human-vibration VDV/MTVV/crest, getting-started ~91 dB
bands, Zwicker sone/phon values, enclosed-space RT spectrum)
- 12 figure-reproduction <details> blocks added (materials x3,
outdoor-propagation x2, time-weighting x2, weighting x3,
speech-intelligibility, getting-started - with an honest note where
the committed figure overlays extra context), all verified runnable
- structural reorders, content-preserving: the exponential detector now
precedes the F/S/I modes; the filter parameter table follows the
comparison it references; weighting opens with 'Where the curves come
from'; block-processing gains a motivating opening and drops its
duplicated constraints list; the raw LaTeX in human-vibration code
spans becomes proper math; F2/F3/F4 defined in prose in intensity
- sound-power SS1-3 gain result figures: three new deterministic
generators (12 PNG variants, ES translations, visually verified)
embedded with captions and <details> using each result's .plot()

* docs: address the review findings on the legacy-conventions batch

- NullFormatter imported from matplotlib.ticker in the SII snippet
(plt.NullFormatter does not exist) (Copilot)
- eps floor inside the log10 of the three FFT-magnitude plots in the
weighting snippets, verified warning-free with -W error (Copilot)
- the getting-started figure snippet now reproduces the committed
figure including the gray PSD overlay, note removed (CodeRabbit)
- 8-tau settling is ~99.97 %, not 99.8 % (CodeRabbit)
- the intensity result generator drops its blanket warning suppression
(this data fires none) and masks non-finite bands instead of
nan_to_num zero bars; regenerated variants are byte-identical
(Gemini, CodeRabbit)
- the outdoor attenuation stacks use separate positive/negative
baselines - the 63 Hz ground term (-4.65 dB) now hangs below zero in
BOTH the snippet and the committed generator figure, whose four
variants regenerate (CodeRabbit, Major)
- the IEC verification claim narrows to what is true: the example
verifies the 200 ms Fast row; CI covers Table 4 down to 1 ms for F
and 2 ms for S (CodeRabbit)
- freqs = res.frequencies added to the three sound-power by-hand blocks
(CodeRabbit)