feat: context pressure denominator, ambient sense formatting, resume timestamp, user nickname system, subagent background fork, settings LLM config, turn lifecycle, ledger lifecycle, subconscious evolution

- Context pressure footer now shows 'ctx 19% of 262k' (B-008)
- Ambient sense formatting as separate timestamp marker (B-010, T-034)
- Resume timestamp indicator with duration (T-032)
- User nickname system sourced from identity frontmatter (T-033)
- Subagent background fork task (B-009, T-031)
- Settings LLM config task (T-030)
- Turn lifecycle and sensorium completion task
- Ledger entry lifecycle task
- Subconscious evolution documentation
- Multimodal input metadata task
- Image support module (src/core/image.rs)
- Various refactors: config, seeds, session, consciousness engine, server modules, bridge, API handlers, TUI cockpit/commands/render, health panel, presence, setup wizard
- website/docs submodule update

Cargo.toml

@@ -61,7 +61,7 @@ ratatui = { version = "0.30", features = ["crossterm"] }  # TUI framework with c
 unicode-width = "0.1"
 arboard = { version = "3", features = ["wayland-data-control"] }  # Clipboard — click-to-copy a message bubble
 colored = "2"       # Color gradients and effects
-image = { version = "0.25", default-features = false, features = ["png", "jpeg"] }  # Per-agent portraits (assets/portrait.{png,jpg})
+image = { version = "0.25", default-features = false, features = ["png", "jpeg", "webp"] }  # Per-agent portraits (assets/portrait.{png,jpg}) + multimodal images
 ratatui-image = "11"  # Real photo rendering in TUI (kitty/sixel/halfblock)
 ratatui-ratty = { version = "0.2", optional = true }  # Inline 3D graphics via Ratty Graphics Protocol