docs(sysrs): SysRS-310 — macOS minimum runtime baseline (v0.9.11)

Author SysRS-310 ratifying the macOS minimum runtime baseline at 10.15
(Catalina) at the SysRS layer, parallel to SysRS-286 (iOS 13.0) and
SysRS-288 (Android API 28).

Closes the Wave 1.5 traceability-audit deferred-but-optional follow-up.
ID allocation: SysRS-310 (not SysRS-290, which is already allocated to
MVP single-active-server-connection scope); monotonic numbering
preserved.

Cross-references SAD-087, SDD-119, SysRS-286, SysRS-288. Verification:
Review + Platform Test on a macOS 10.15 system. Raising the baseline
(e.g., to 11.0 / Big Sur) requires a DEC entry.

Trace: SysRS v0.9.11, SAD-087, SDD-119.

docs/requirements/sysrs.md

@@ -2,7 +2,7 @@
 
 **Product name:** Chanora  
 **Document type:** SysRS / System Requirements Specification  
-**Version:** 0.9.10
+**Version:** 0.9.11
 **Status:** Baseline Candidate  
 **Product category:** Cross-platform voice client application  
 **Architecture:** Flutter + Rust Core  
@@ -1959,6 +1959,11 @@ This section converts the baseline product decisions into auditable system-level
 - Priority: P0
 - Verification: Review (SysDes/SAD declaration of tolerance value is present and is referenced by the CI workflow definition)
 
+**SysRS-310**: The Chanora application system shall support macOS runtime deployment on macOS 10.15 (Catalina) or later as the minimum supported runtime, unless Flutter, plugin, audio, or platform constraints require raising the minimum version. This clause ratifies at the SysRS layer the existing macOS baseline already encoded in `apps/chanora_flutter/macos/chanora_bridge.podspec` (`MACOSX_DEPLOYMENT_TARGET = 10.15`) and provides explicit cross-platform-baseline coverage parallel to SysRS-286 (iOS) and SysRS-288 (Android). Rationale: macOS 10.15 is the floor that supports the modern CoreAudio / AVAudioEngine voice-processing-IO surfaces relied on by the realtime audio path, native arm64 Apple Silicon builds (no Rosetta dependence), and the SDK version used by the existing podspec lipo step that produces the universal binary; a lower minimum would require backporting audio code paths or shipping a non-universal build, neither of which is in P0-MVP scope. The minimum may be raised further (for example, to macOS 11.0 / Big Sur for native Apple Silicon performance gains) only via a superseding accepted decision recorded as a DEC entry; it shall not be lowered without a superseding accepted decision. Cross-references: SAD-087 (architectural macOS runtime allocation), SDD-119 (macOS bridge build pipeline consuming this baseline), SysRS-286 (iOS minimum runtime parallel), SysRS-288 (Android minimum runtime parallel). ID-allocation note: this clause uses SysRS-310 rather than the structurally parallel SysRS-290 because SysRS-290 is already allocated (MVP single-active-server-connection scope); monotonic numbering convention is preserved.
+
+- Priority: P0
+- Verification: Review (the SysRS baseline matches the podspec `MACOSX_DEPLOYMENT_TARGET` setting), Platform Test (the produced macOS binary runs on a macOS 10.15 system)
+
 
 ## 32. Change History Addendum
 
@@ -1998,4 +2003,5 @@ This section converts the baseline product decisions into auditable system-level
 
 | Version | Date | Description |
 |---|---|---|
+| 0.9.11 | 2026-05-18 | Closed the Wave 1.5 traceability-audit deferred-but-optional follow-up by adding SysRS-310 (macOS minimum runtime baseline at macOS 10.15 / Catalina), ratifying at SysRS layer the existing `apps/chanora_flutter/macos/chanora_bridge.podspec` `MACOSX_DEPLOYMENT_TARGET = 10.15` setting and providing explicit cross-platform-baseline coverage parallel to SysRS-286 (iOS) and SysRS-288 (Android). Allocated SysRS-310 rather than SysRS-290 because SysRS-290 is already taken (MVP single-active-server-connection scope); monotonic numbering convention preserved. No change to the numeric baseline value; any future raise (e.g., to macOS 11.0 / Big Sur for native Apple Silicon performance gains) is flagged as a DEC-level change, not authored here. |
 | 0.9.10 | 2026-05-18 | Authorized Option B of the benchmark-infrastructure decision for the realtime audio path. Added SysRS-307 (maintained numeric performance baselines for the realtime audio capture and playback paths — heap allocation count per callback after warmup, per-callback wall-clock budget relative to the audio frame period, Opus encode/decode latency, and resampler throughput at common rate-pair conversions; extends SysRS-180/SysRS-181 from prescriptive intent into a measurable contract; consistent with SysRS-186 and SysRS-236). Added SysRS-308 (advisory CI regression reporting executing the benchmark suite on every PR and every merge to the default branch on at least one host architecture, surfacing results in the PR status-check view; explicitly **advisory only** — does not fail the build, does not block merge; escalation to a build-failing hard gate is out of scope and deferred to a future SysRS clause after baseline maturity; consistent with the SysRS-234..239 verification-family pattern). Added SysRS-309 (explicitly declared numeric tolerance window for the advisory comparison; numeric value(s) and comparison methodology delegated to SysDes/SAD; suggested starting value +20% recorded as non-binding downstream guidance). All three new clauses are consistent with SysRS-295 (no automatic telemetry / diagnostic upload in MVP) — they neither authorize nor require off-device transmission of measurement data beyond the existing CI provider surface visible to repository collaborators. Explicitly **NOT** authored in this update: (a) Dimension 3 production telemetry export of timing histograms (deferred to P1; any future opt-in performance-evidence export through the user-initiated diagnostic-export path requires a separate P1 SysRS clause and must be reconciled with SysRS-295 at that time); (b) build-failing hard CI gate (deferred to a future SysRS clause). |