feat(engine,ui): unify detection in rules engine, add function rules & per-script matches; improve scripts table UX

Core changes
- Centralize detection in the Rules Engine; browser.py now focuses on fetch/extract/persist.
- Add class-based adapters:
  - FactAdapter: converts snippets → structured facts.
  - FunctionRuleAdapter: wraps dict-based rule functions for engine input (str or dict).
- Register function rules (code-based) alongside YAML rules:
  - form_action_missing
  - form_http_on_https_page
  - form_submits_to_different_host
  - script_src_uses_data_or_blob
  - script_src_has_dangerous_extension
  - script_third_party_host

Rules & YAML
- Expand/normalize YAML rules with severities + tags; tighten patterns.
- Add new regex rules: new_function_usage, unescape_usage, string_timer_usage, long_hex_constants.
- Move iframe rule to `text` category.
- Keep existing script/form/text rules; all compile under IGNORECASE.

Browser / analysis refactor
- browser.py:
  - Remove inline heuristics; rely on engine for PASS/FAIL, reason, severity, tags.
  - Build page-level overview (`rule_checks`) across categories.
  - Analyze forms: add `base_url` + `base_hostname` to snippet so function rules can evaluate; include per-form rule_checks.
  - Analyze scripts: **per-script evaluation**:
    - Inline -> run regex script rules on inline text.
    - External -> run function script rules with a facts dict (src/src_hostname/base_url/base_hostname).
    - Only include scripts that matched ≥1 rule; attach severity/tags to matches.
  - Persist single source of truth: `/data/<uuid>/results.json`.
  - Backward-compat: `fetch_page_artifacts(..., engine=...)` kwarg accepted/ignored.

UI/UX
- Suspicious Scripts table now shows only matched scripts.
- Add severity badges and tag chips; tooltips show rule description.
- Prevent table blowouts:
  - Fixed layout + ellipsis + wrapping helpers (`.scripts-table`, `.breakable`, `details pre.code`).
  - Shortened inline snippet preview (configurable).
- Minor template niceties (e.g., rel="noopener" on external links where applicable).

Config
- Add `ui.snippet_preview_len` to settings.yaml; default 160.
- Load into `app.config["SNIPPET_PREVIEW_LEN"]` and use in `analyze_scripts`.

Init / wiring
- Import and register function rules as `Rule(...)` objects (not dicts).
- Hook Rules Engine to Flask logger for verbose/diagnostic output.
- Log totals on startup; keep YAML path override via `SNEAKYSCOPE_RULES_FILE`.

Bug fixes
- Fix boot crash: pass `Rule` instances to `engine.add_rule()` instead of dicts.
- Fix “N/A” in scripts table by actually computing per-script matches.
- Ensure form rules fire by including `base_url`/`base_hostname` in form snippets.

Roadmap
- Update roadmap to reflect completed items:
  - “Show each check and whether it triggered (pass/fail list per rule)”
  - Severity levels + tags in Suspicious Scripts
  - Results.json as route source of truth
  - Scripts table UX (badges, tooltips, layout fix)

docs/Feature Session Plan Template.md

@@ -0,0 +1,31 @@
+# Feature Session Plan – SneakyScope
+
+**Feature:**
+
+* \[Short description of the feature or improvement]
+
+**Effort:**
+
+* Easy / Medium / Hard
+
+**Dependencies:**
+
+* \[List of prerequisites or related tasks that must be done first]
+
+**Design Notes:**
+
+* \[Goals, considerations, analyst/UX needs, edge cases, pitfalls to avoid]
+
+**Implementation Tasks:**
+
+* [ ] Step 1 – …
+* [ ] Step 2 – …
+* [ ] Step 3 – …
+
+**Validation / Testing:**
+
+* \[How we’ll verify it works — e.g., test cases, UI check, API output, logs]
+
+**Next Steps After Completion:**
+
+* \[What this unblocks or enables, i.e. the next feature/dependency]