docs: sync website + README + wizard guide + changelog with new features

docs/index.html (kportal.raczylo.com):
  - Features grid gains Bulk Generate, Sensitive Header Redaction,
    Verified Installer cards; Headless card subtext clarified to
    'logs to stderr'.
  - Keybindings: 'a' -> 'n' for Add (matches real binding).
  - Quick Install card notes SHA-256 + optional cosign verification
    and DRY_RUN / SKIP_COSIGN env vars.
  - New Bulk Generate usage tile with --dry-run hint; Headless tile
    redirects stderr.
  - HTTP Traffic Logging card mentions automatic header redaction
    and the wizard 'h' toggle.

README.md:
  - install.sh note expanded with DRY_RUN/SKIP_COSIGN table.
  - HTTP Traffic Logging section gains 'Toggling per-forward
    logging', 'Header redaction', and 'Advanced configuration'
    examples.
  - Headless mode clarified to log to stderr (2>kportal.log).
  - Troubleshooting note on accepted context-name characters.

WIZARD_USAGE.md:
  - Add binding corrected from 'a' to 'n'; 'e' (edit) row added.
  - 'h' httpLog toggle and Tab focus switch documented.
  - New 'Edit Forward Wizard' section noting same-port allowed and
    advanced httpLog preserved.
  - Esc-cancels-delete behaviour clarified.

CHANGELOG.md: [Unreleased] populated with Added / Changed / Fixed
entries for this session's user-facing work, dated 2026-05-06.

.kportal.yaml example: inline 'httpLog: true' comment on one
forward as a usage hint.

.kportal.yaml

@@ -34,6 +34,7 @@ contexts:
             port: 8080
             localPort: 8080
             alias: prod-api
+            httpLog: true             # Enable HTTP traffic logging for this forward (press 'l' in the TUI)
 
           # Forward to PostgreSQL database
           - resource: service/postgres