feat(ttp): show canonical ATT&CK technique names in the TTPs UI

"T1595" alone is opaque; "T1595 — Active Scanning" tells you the
story at a glance. The names come from a backend-side static catalogue
pinned to the same ATT&CK release as the rule engine
(_ATTACK_RELEASE = "v15.1") — names are the canonical MITRE labels,
not author-supplied strings on rules, so a rule author can't typo a
name and the entire fleet sees the typo.

- New `decnet/ttp/attack_catalog.py` with `TECHNIQUE_NAMES` covering
  every technique_id + sub_technique_id emitted by `rules/ttp/`
  (R0001..R0058 → 69 IDs in the v0 pack).
- `IdentityTechniqueRow` / `TechniqueRollupRow` / `CampaignTechniqueRow`
  / `TTPTagDetailRow` gain optional `technique_name` /
  `sub_technique_name` fields. Repo + router populate them from the
  catalogue at row-construction time. None when an ID isn't in the
  catalogue — UI falls back to the bare ID.
- Coverage test (`tests/ttp/test_attack_catalog.py`) walks every
  YAML rule and asserts every emitted ID has a catalogue entry, so
  a future rule author who forgets to update the catalogue gets a
  loud failure rather than a silent UI fallback.

Frontend:
- `TTPsObservedSection` shows "T1595.002 — Active Scanning:
  Vulnerability Scanning" instead of just the ID, with overflow
  ellipsis + tooltip for narrow viewports. Inspector header /
  TECHNIQUE row also surface the names.

decnet/web/router/ttp/api_get_tag_details.py

@@ -25,6 +25,7 @@ from typing import Any, Literal
 from fastapi import APIRouter, Depends, HTTPException, status
 
 from decnet.telemetry import traced as _traced
+from decnet.ttp.attack_catalog import technique_name as _technique_name
 from decnet.web.db.models import TTPTagDetailRow
 from decnet.web.dependencies import repo, require_viewer
 
@@ -71,4 +72,11 @@ async def api_ttp_tag_details(
         sub_technique_id=sub_technique_id,
         limit=limit,
     )
-    return [TTPTagDetailRow(**row) for row in rows]
+    return [
+        TTPTagDetailRow(
+            **row,
+            technique_name=_technique_name(row.get("technique_id")),
+            sub_technique_name=_technique_name(row.get("sub_technique_id")),
+        )
+        for row in rows
+    ]