fix: HA renders full lidar map (drain chunked history stream)

[Leicas]

Problem

Reported in renjfk/OpenNeato#132: the Home Assistant integration renders only a partial lidar/history map, while the OpenNeato web dashboard shows the full map for the same robot and session.

Root cause

A multi-agent investigation (3 architects + dev) converged with high confidence on a chunked-stream truncation in the API client — not a rendering bug.

The firmware serves GET /api/history/<file> as an HTTP chunked transfer with no Content-Length (firmware/src/web_server.cpp:454, beginChunkedResponse). The HA client did a single bounded read:

raw = await response.content.read(MAX_HISTORY_RESPONSE_BYTES + 1)

On a chunked aiohttp response, read(n) returns as soon as any data is buffered — it does not block until n bytes or EOF. HA therefore decoded only the first chunk(s): a truncated JSONL prefix, far below the 2 MiB cap (so the cap check passed silently). parse_session_jsonl then silently dropped every pose past the cut (its json.loads is wrapped in try/except → continue), rendering a subset of the path → a partial map.

The frontend hits the same endpoint but uses await res.text() (frontend/src/api.ts:81), which drains the stream to EOF — hence the full dashboard map.

Changes

• api.py get_history_session() — single read → async for chunk in response.content.iter_chunked(65536) accumulate-to-EOF, with the size cap enforced incrementally (matches the frontend's res.text() semantics). Primary fix.
• history_renderer.py parse_session_jsonl() — log a warning when the final line fails to parse (the classic truncation signature) so any future silent truncation is observable.
• lidar_renderer.py to_canvas() — radians(90 - angle) → radians(90 + angle) to match the frontend (lidar-map.tsx); fixes a separate horizontal mirror on the live lidar view (orientation only, orthogonal to the partial-map bug).

Firmware needs no change — it already serves complete data. This is an HA-integration-only fix shipped via HACS.

Verification

Against a live bridge:

1. Log len(buf) in get_history_session — before, much smaller than the firmware session file; after, equals the full decompressed JSONL.
2. Log len(poses) in parse_session_jsonl — jumps to the full set; no truncation warning on a healthy download.
3. Compare the HA history camera image vs the frontend replay for the same session — extents now match.

All three files py_compile clean.

Fixes renjfk#132

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Fixes a Home Assistant integration bug where the lidar history map was rendered partially because get_history_session() did a single bounded content.read(n) against the firmware's chunked-transfer endpoint, which returns as soon as any buffered data is available rather than blocking to EOF. The fix drains the chunked response with iter_chunked while incrementally enforcing the size cap, mirroring the frontend's res.text() semantics. Two adjacent improvements are bundled: a warning when the final JSONL line fails to parse (truncation signature), and a sign-flip in lidar_renderer.to_canvas to match the frontend orientation.

Changes:

• Drain the chunked /api/history/<file> response to EOF in api.py to avoid truncated downloads.
• Log a warning in parse_session_jsonl when the final line fails to parse, surfacing future silent truncation.
• Align Python lidar to_canvas formula (90 + angle) with lidar-map.tsx, fixing a horizontal mirror.
• Update .github/ISSUE_TEMPLATE/config.yml discussions URL to the Leicas fork (consistent with README fork positioning).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
custom_components/openneato/api.py	Replace single bounded read with iter_chunked accumulation + incremental size cap.
custom_components/openneato/history_renderer.py	Warn when final JSONL line is unparseable (truncation indicator).
custom_components/openneato/lidar_renderer.py	Switch to_canvas to 90 + angle to match frontend reference.
.github/ISSUE_TEMPLATE/config.yml	Point discussions link at the Leicas fork.

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