Update ADR Inventory

Rebuild the inventory table in docs/adrs/README.md so it reflects the current set of ADR files and their metadata.

Critical: Minimise diff noise

Only touch rows that actually changed. When adding a new ADR, append a row matching the existing column widths — do NOT reformat the header, separator, or unchanged data rows. When updating an ADR's status or title, edit only that row's cell content and pad to match the existing column width. The goal is a minimal, reviewable git diff.

Procedure

1. Read the current inventory. Read docs/adrs/README.md and parse the existing table to understand current column widths and which ADRs are already listed (with their status and title).
2. Find all ADR files. Glob for docs/adrs/adr-*.md (exclude README.md). Sort results in natural numeric order by ADR number.
3. Extract metadata from each ADR file. For every file, read the first ~10 lines and extract:
   • ADR number and title from the level-1 heading: # ADR-NNNN: Title
   • Status from the ## Status section (the first non-empty line after ## Status)
4. Determine the date. Use git to get the author date of the commit that first introduced the file:

   git log --diff-filter=A --follow --format="%as" -- <file> | tail -1

   If the file is untracked (no git history), use today's date.

5. Map status text to the table format. Normalise the raw status string (strip any existing emoji) and apply the project's status legend:

   Raw (case-insensitive)	Table display
   Proposed	🟡 Proposed
   Accepted	✅ Accepted
   Deprecated	❌ Deprecated
   Superseded	🔄 Superseded

   If the status does not match any of the above, use the raw text as-is.

6. Compare and apply minimal edits.

   • New ADRs: Append a row, padding each cell to match the existing column widths (right-pad with spaces). Do not alter the header or separator rows unless the new content exceeds an existing column width.
   • Changed status/title: Edit only the affected cell(s) in the existing row, adjusting padding to maintain alignment.
   • Removed ADRs: Delete only that row.
   • No changes: Do nothing — do not rewrite the table.

   Only widen columns (header, separator, and all data rows) if new content exceeds the current column width. Never shrink columns.

7. Report what changed. Tell the user which ADRs were added, removed, or updated compared to the previous inventory, or confirm that the inventory was already up to date.