fix(memory): make recorder lossless under load

[TomCC7]

Summary

Fix Recorder data loss under sustained sensor load and temporary encoder or SQLite stalls. Every message accepted by Recorder is persisted in callback-arrival order, or recording fails visibly.

Approach

• Add an opt-in bounded queue to pSHMTransport; its default remains the existing latest-value transport.
• Bypass Recorder's latest-value dispatcher and feed one bounded FIFO worker, which serially calls the existing Stream.append() path.
• Stop subscriptions, wait for in-flight callbacks to enqueue, then drain accepted work; surface queue overflow, processing/write failure, or drain timeout.

Verification

The standalone recorder benchmark compares the generated source manifest with the completed memory2 database. Its 30-second production profile contains 22,500 observations: RGB 30 Hz, two grayscale streams at 30 Hz, depth 30 Hz, IMU 400 Hz, PointLIO 10 Hz, odometry 200 Hz, and TF 20 Hz.

All three experiments stored 22,500/22,500 observations with no missing, duplicate, corrupt, or reordered payloads:

• baseline
• one-second depth encoder stall
• SQLite writer lock

Each run sustained 64.85 MiB/s offered raw data, 38.88 MiB/s encoded payload, and about 39.07 MiB/s SQLite growth.

• Targeted Recorder tests: 11 passed
• Broad memory/pubsub/recorder suite: 511 passed, 1 deselected
• Ruff, strict mypy, and all hooks applicable to changed files passed

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[codecov]

Codecov Report

❌ Patch coverage is 85.91954% with 49 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
dimos/memory/recording.py	79.61%	12 Missing and 9 partials ⚠️
dimos/memory/module.py	69.69%	16 Missing and 4 partials ⚠️
dimos/memory/test_recording.py	94.24%	6 Missing and 2 partials ⚠️

@@            Coverage Diff             @@
##             main    #3558      +/-   ##
==========================================
+ Coverage   77.10%   77.15%   +0.04%     
==========================================
  Files        1262     1264       +2     
  Lines      120300   120626     +326     
  Branches    10634    11238     +604     
==========================================
+ Hits        92758    93067     +309     
- Misses      24461    24462       +1     
- Partials     3081     3097      +16     

Flag	Coverage Δ
OS-ubuntu-24.04-arm	72.05% <82.47%> (+0.06%)	⬆️
OS-ubuntu-latest	73.94% <85.91%> (+0.05%)	⬆️
Py-3.10	73.93% <85.91%> (+0.05%)	⬆️
Py-3.11	73.94% <85.91%> (+0.05%)	⬆️
Py-3.12	73.94% <85.91%> (+0.05%)	⬆️
Py-3.13	73.94% <85.91%> (+0.05%)	⬆️
Py-3.14	73.94% <85.91%> (+0.05%)	⬆️
Py-3.14t	73.94% <85.91%> (+0.05%)	⬆️
SelfHosted-Large	30.01% <20.97%> (-0.03%)	⬇️
SelfHosted-Linux	35.12% <20.97%> (-0.04%)	⬇️

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Files with missing lines	Coverage Δ
dimos/core/transport.py	71.73% <100.00%> (+2.74%)	⬆️
dimos/protocol/pubsub/impl/shmpubsub.py	76.16% <100.00%> (+0.89%)	⬆️
dimos/protocol/pubsub/test_registry.py	97.14% <100.00%> (+1.09%)	⬆️
dimos/memory/test_recording.py	94.24% <94.24%> (ø)
dimos/memory/module.py	61.73% <69.69%> (+5.21%)	⬆️
dimos/memory/recording.py	79.61% <79.61%> (ø)

... and 3 files with indirect coverage changes

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