[AZ-618] [AZ-619] [AZ-620] [AZ-621] [AZ-622] [AZ-623] [AZ-624] Split AZ-618 into 6 subtasks per spec sizing-note

The AZ-618 spec author flagged "likely a true 8" with a recommended
6-subtask split; combined with the user-rule cap on PBI complexity
(create at 2-3pt, max 5pt) the right move was to split before any
implementation began. Subtasks created in Jira as children of AZ-618:

  AZ-619 (Phase A) c13_fdr + clock                       2pt
  AZ-620 (Phase B) c6_descriptor_index + c6_tile_store   3pt
  AZ-621 (Phase C) c7_inference engine                   3pt
  AZ-622 (Phase D) c3_lightglue_runtime + c3_feature_extractor 3pt
  AZ-623 (Phase E) c282_ransac_filter + c5 helpers       3pt
  AZ-624 (Phase F) wire main() + AC-1..AC-5 + Jetson     2pt

Aggregate: 16pt actionable work (vs. AZ-618's original 5pt filing,
which the author had already qualified as understated). AZ-618 stays
In Progress in Jira as the umbrella tracker; its task spec file is
now an umbrella reference pointing to the 6 phase-specific spec files.

Deps table updated: AZ-618 row reduced to 0pt with subtask deps; six
new rows added; header counts refreshed (156 -> 162 tasks, 522 -> 533
points). Autodev state set to phase=1 (parse) for the next batch =
AZ-619 (Phase A) only.

Co-authored-by: Cursor <cursoragent@cursor.com>

_docs/_autodev_state.md

@@ -8,7 +8,7 @@ status: in_progress
 sub_step:
   phase: 1
   name: parse
-  detail: "AZ-618 single-task batch (rewind from Step 11)"
+  detail: "AZ-618 split into AZ-619..AZ-624 (subtasks of AZ-618; epic AZ-602). Next batch = AZ-619 (Phase A: c13_fdr + clock, 2pt). AZ-618 stays In Progress as umbrella; subtasks are To Do."
 retry_count: 0
 cycle: 1
 tracker: jira