feat(apply,interview): cache company research to skip repeat lookups (#349)

/apply Step 3's reviewer agent and /interview Step 2 each independently
execute the Company Research Checklist (04-job-evaluation.md) for the
same company - applying to a role and later prepping for its interview
researches the company twice from scratch, same WebSearch/WebFetch cost
both times, no sharing between the two commands.

Adds a company_research/<normalized-name>.json cache (30-day TTL) that
either consumer checks before researching and writes after a fresh
pass. Defined once in 04-job-evaluation.md, next to the checklist it
mirrors, so both commands point at one source instead of restating the
schema. Does not change the verification model: 03-writing-style.md
rule 5 already treats reviewer-agent research as a lead, not a source,
requiring independent re-confirmation before any company claim ships
in a final artifact - the cache stores source URLs alongside each
fact so that re-confirmation stays cheap, but the requirement itself
is untouched and restated in both consumers.

company_research/*.json added to .gitignore and security_guards.py's
REQUIRED_IGNORE_RULES as a plain rooted pattern (not **/-prefixed):
the cache is referenced from commands, not a skill, so it resolves
against the repo root normally, unlike job_scraper/upskill's
skill-relative paths.

Pinned by tests/test_company_research_cache.py, mirroring the
spec-pinning pattern in test_rank_command.py and test_onboarding_privacy.py.
The write-back assertions for both apply.md and interview.md were
verified to actually fail against the regression they guard (the
instruction stripped, confirmed the test catches it, restored) before
being considered done - the write half is the one most likely to be
dropped silently in a future edit, since the read half is the more
obvious change to make.

framework_version bumped 1.2.4 -> 1.2.5 in 04-job-evaluation.md, the
only touched file inside the tracked skill set.

.claude/skills/job-application-assistant/04-job-evaluation.md

@@ -1,5 +1,5 @@
 ---
-framework_version: 1.2.4
+framework_version: 1.2.5
 ---
 
 # Job Evaluation Framework
@@ -179,6 +179,52 @@ Present the evaluation as:
 - [ ] Identified network contacts who may know the team/manager
 ```
 
+## Company Research Cache
+
+The Company Research Checklist above is executed independently by `/apply` Step 3's
+reviewer agent and by `/interview` Step 2 - the same company, researched from scratch
+twice when the two commands run against the same application. This cache lets either
+consumer reuse a recent result instead of repeating the search/fetch work.
+
+**This does not change how a claim gets verified.** `03-writing-style.md` rule 5 and
+`/interview`'s own Step 2 already require that any company-specific claim landing in a
+final artifact (cover letter, interview prep pack) be independently re-confirmed before
+inclusion, regardless of source - a cache hit is a lead, exactly like reviewer-agent
+research already is, never a substitute for that final check. The cache only removes
+repeated *discovery* work: it stores where each fact came from, so re-confirming a
+specific claim means re-fetching a known URL instead of re-searching for it.
+
+**File:** `company_research/<normalized-company-name>.json`, one file per company.
+Normalize the company name for the filename: lowercase, trim, spaces to hyphens (e.g.
+`Acme Corp` -> `acme-corp.json`). No legal-suffix normalization - a near-miss on a
+different spelling just costs a cache miss and a fresh (correct) research pass, never a
+wrong answer.
+
+**TTL:** 30 days from `fetched_date`. A conservative default, easy to change here alone
+since both consumers read this section rather than hardcoding a number of their own.
+
+**Schema** (fields mirror the Company Research Checklist's own categories above):
+```json
+{
+  "company": "Acme Corp",
+  "fetched_date": "YYYY-MM-DD",
+  "sources": {
+    "website": {"url": "...", "notes": "mission, values, recent news"},
+    "reviews": {"url": "...", "notes": "..."},
+    "linkedin": {"url": "...", "notes": "team size, recent hires"},
+    "media": {"url": "...", "notes": "..."}
+  },
+  "network_contacts_note": "..."
+}
+```
+
+**Before researching a company**, check for `company_research/<normalized-name>.json`.
+If it exists and `fetched_date` is within the 30-day TTL, use its contents as the
+starting point instead of searching from scratch - still subject to the final-claim
+verification rule above. If it is missing or stale, research per the checklist as usual,
+then write (or overwrite) the file with fresh findings and today's date, so the next
+consumer benefits.
+
 ## Weighting
 - Technical Skills: 30%
 - Experience Match: 25%