feat(game): complete authoritative gameplay mechanics

PLANS.md

@@ -555,12 +555,12 @@ server-enforced role-specific visibility.
   A live `GET /health` returned
   `{"status":"serving","healthy":true,"version":"0.6.0","errorCode":0}`.
   These host, serialization, build, resource, and physical-board results
-  provide concrete evidence for all six acceptance criteria. Milestone 007
-  remains `NOT_STARTED`.
+  provide concrete evidence for all six acceptance criteria and complete
+  Milestone 006.
 
 ## Milestone 007 — Keys, artifacts, compasses, exits, and results
 
-**Status:** `NOT_STARTED`
+**Status:** `COMPLETE`
 
 ### Objective
 
@@ -592,9 +592,68 @@ Complete the authoritative gameplay mechanics and terminal match outcomes.
 
 ### Evidence
 
-Completion evidence is not yet available because this milestone has not
-started. Required evidence includes complete mechanic tests and timestamped
-result-window tests.
+- `bash scripts/run_host_tests.sh` completed successfully. Its new deterministic
+  mechanics suite reported `game key inventory, drop, and sabotage: PASS`,
+  `game atomic meeting key return: PASS (opponent keys swapped to owners)`,
+  `game owner-only exit opening and outward move: PASS`, `game one-use vision
+  duration: PASS (10 successful moves, failed move ignored)`, `game compass
+  bearing and role-specific projections: PASS`, and `game outward result
+  window: PASS (200 ms draw boundary, 201 ms winner)`. All Milestone 001-006
+  host regressions and the reproducible web-asset check passed in the same run.
+- The key tests exercised pickup of both owner and opponent keys, one-slot
+  rejection, opponent-key sabotage, deterministic pickup when both keys occupy
+  one cell, voluntary drop, and rejected empty drop. They asserted after every
+  transition that each key existed exactly once on the ground or in one
+  inventory. A crossed-key meeting cleared both inventories and reassigned the
+  keys to their owners in one state transition.
+- Exit tests proved that the wrong key cannot open a player's own exit and that
+  neither carrying the opponent's key nor standing at the opponent's exit
+  permits opening or an outward move. Carrying the matching key opened only the
+  owner's exit; a later outward boundary command was required to enter the
+  finish window. Timestamped cases proved that the second outward move at
+  exactly 200 ms produces a draw, while advancing time at 201 ms finalizes the
+  first player as winner; the symmetric Player 2 winner case also passed.
+- Artifact tests consumed an artifact once, selected the authoritative radius
+  six, retained all ten moves after entry, ignored a failed move, and returned
+  to radius three after exactly ten later successful moves. Compass tests
+  produced the direct eight-way bearing to only the activating player's own
+  exit, preserved it across a rejected command, and cleared it on the next
+  successful move.
+- Projection inspection covered both player roles and the observer. Player
+  snapshots contained only their own inventory, effect, compass hint, and exit
+  state; an opponent's carried key appeared only while that opponent was
+  visible and disappeared when hidden. Observer snapshots contained both
+  inventories, effects, hints, exit states and timestamps, all remaining
+  ground objects, and the result. The complete default `128 x 64` observer
+  snapshot serialized into 688 versioned chunks with a worst-case maximum of
+  471 bytes, below the 512-byte message bound. Independent AddressSanitizer and
+  UndefinedBehaviorSanitizer runs of both game suites passed without findings;
+  leak detection was disabled because the sandbox executes under `ptrace`.
+- `PLATFORMIO_SETTING_ENABLE_TELEMETRY=no
+  /home/sasa/.platformio/penv/bin/pio project config` parsed the locked
+  `espressif32@7.0.1`, ESP-IDF, `esp32-c6-devkitm-1`, `partitions.csv`, and
+  `sdkconfig.defaults` configuration, including the isolated
+  `milestone-007-device-test` environment. `/home/sasa/.platformio/penv/bin/pio
+  run -e esp32-c6-devkitm-1` completed with `[SUCCESS]`, reporting 47,508 of
+  327,680 RAM bytes and 1,005,274 of 2,097,152 application bytes; the independent
+  partition check reported `firmware.bin uses 1005904/2097152 bytes in
+  partition factory`. The isolated device image also built with `[SUCCESS]`,
+  using 124,628 RAM bytes and 1,020,168 application bytes, with
+  `firmware.bin uses 1020800/2097152 bytes in partition factory`.
+- `/home/sasa/.platformio/penv/bin/pio run -e esp32-c6-devkitm-1 --target
+  buildfs` completed with `[SUCCESS]`; the partition check reported
+  `littlefs.bin uses 2031616/2031616 bytes in partition littlefs`. The test image
+  upload identified an ESP32-C6FH4 revision 0.2 with 4 MB embedded Flash and
+  hash-verified each write. The board logged `M007 events: artifact=0, key=0,
+  hint=8, opened=1, outward=1, result=1, sequence=6`, player and complete
+  observer projections, `fixed=34776/40960 bytes, runtime=6/50 ms,
+  heap_delta=0`, and `M007 physical mechanics test: PASS`.
+- The normal firmware was restored and hash-verified after the isolated test.
+  A live `GET /health` returned
+  `{"status":"serving","healthy":true,"version":"0.7.0","errorCode":0}`.
+  These deterministic, security-boundary, size, sanitizer, and physical-board
+  results provide concrete evidence for all six acceptance criteria. Milestone
+  008 remains `NOT_STARTED`.
 
 ## Milestone 008 — Player browser experience