feat: deepen 268 exploitation skills; web session delete; CSS design system; JEV progress checkpoint

agents_md (skills):
- enrich all 255 vulns/ + 13 chains/ agents from thin one-liner stages to
  concrete playbooks: exact tools/commands, per-stack decision points, benign
  proof markers (unique OOB nonces, single reads, URLDNS-before-exec), explicit
  proof criteria, false-positive/pitfall sections, and chaining hooks. Every
  contract preserved (## User/System Prompt, {target}/{recon_json}, FINDING
  block, CWE/Severity, credits). avg 37->53 lines; loader parses all 449.

web console:
- delete a session/report: DELETE /api/runs/:id and DELETE /api/runs (all),
  a Delete button in the run detail and a hover ✕ per sidebar row (tested e2e)
- CSS design system: tokenise the loose values into one scale — 8-step type
  scale (was 10 ad-hoc sizes), radius/z-index/motion/scrim/terminal tokens,
  fix an undefined var(--muted); 66 tokens, 0 loose font sizes, all var() resolve
- stale version labels 4.0.0/4.2.0 -> 4.2.1

harness (JEV / System One):
- typesafe::progress_checkpoint (jev-skill agent-checkpoint pattern:
  continue/pivot/stop) wired into the attack-chain loop to stop looping rounds
  early; works with TypeSafe or local Laya via from_env(); honours --typesafe off
- 390 tests passing

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agents_md/vulns/js_source_deep_analysis.md

@@ -35,5 +35,6 @@ FINDING:
 - Impact: [what you reached]
 - Remediation: [server-side enforcement / rotate the key / remove the source map]
 ```
+- Chaining hooks: recovered API routes/params → IDOR/BOLA & mass-assignment targets; a working key → cloud/service pivot; an admin route with only a client guard → call its API to prove the server-side gap; a traced sink with a reachable source → DOM XSS.
 ## System Prompt
 You read the bundle to find what the server forgot to enforce. A string in JavaScript is a lead, never a finding: an admin route in the bundle is only a finding when you call its API and the server answers; a key in the source is only a finding when you show what it unlocks. Prefer source maps over minified guessing, quote file:line, and always pair a client-side discovery with the server request that proves or disproves it. Report unverified keys as leads, explicitly labelled.