v1.3.0: Bedrock translator refactor, usage metrics, session restore fixes, and predefined rules

Major changes:

- **Bedrock translator architecture**: Extract orchestration logic from `impl.rs` into
  a dedicated `translator.rs` module. Rename `convert_request.rs` → `request_translator.rs`
  and `stream.rs` → `response_translator.rs` for clarity. Remove `tool_docs.rs` (inlined).
  Remove `fallback_to_warp` setting and server fallback path — Bedrock is now the sole backend.

- **Unknown tool handling**: The response translator now detects hallucinated/unknown tool
  calls from the model and synthesizes error tool_results so the conversation doesn't
  deadlock waiting for a result that will never come.

- **Usage display overhaul**: Replace credit-based usage display with detailed token metrics
  showing context window %, cache hit rate (read/write/miss), and estimated cost in dollars.
  Add `total_input_tokens`, `total_cache_read_tokens`, `total_cache_write_tokens`, and
  `cache_miss_tokens` accessors to `AIConversation`.

- **Predefined rules system**: Add `predefined_rules.rs` with 11 system-defined behavioral
  rules that are auto-seeded on first launch. Add "Add Predefined Rules" button to the
  Rules UI for re-adding them later. Track seeding state via `has_seeded_predefined_rules`
  setting.

- **Session restore improvements**: Rename database file from `warp.sqlite` to
  `galaxy.sqlite` with automatic migration from both same-directory and state_dir legacy
  paths. Improve CWD persistence by falling back to `session_startup_path` for agent-mode
  and fresh tabs. Add extensive session-save/restore logging.

- **Shell bootstrap rebrand**: Rename `WARP_INITIAL_WORKING_DIR` environment variable to
  `GALAXY_INITIAL_WORKING_DIR` across bash, zsh, and fish bootstrap scripts.

- **Model defaults**: Change default Bedrock model from Opus 4.7 to Opus 4.6.
  Add `context_window_for_model()` helper with model-aware context sizes.
  Remove `is_bedrock_model()` (no longer needed without server fallback).

- **User query persistence**: The response translator now emits a `UserQuery` proto message
  at stream start so the user's prompt persists across sessions for conversation titles.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src/ai/bedrock/client.rs

@@ -11,7 +11,7 @@ use super::external_config::ExternalBedrockConfig;
 use super::convert::{build_converse_request, ConversationMessage, ToolDefinition};
 use super::diagnostic::BedrockDiagnosticLogger;
 use super::models::apply_cross_region_prefix;
-use super::stream::bedrock_stream_to_response_events;
+use super::response_translator::bedrock_stream_to_response_events;
 use crate::ai::agent::api::ResponseStream;
 
 pub struct BedrockClient {
@@ -27,7 +27,6 @@ pub struct BedrockClientConfig {
     pub access_key_id: String,
     pub secret_access_key: String,
     pub cross_region_inference: bool,
-    pub fallback_to_warp: bool,
 }
 
 impl BedrockClientConfig {
@@ -63,8 +62,6 @@ pub enum BedrockError {
     CredentialsNotConfigured,
     #[error("Bedrock region not configured and could not be auto-detected")]
     RegionNotConfigured,
-    #[error("AWS credential error: {0}")]
-    CredentialError(String),
     #[error("Bedrock API error: {0}")]
     ApiError(String),
     #[error("Model not found: {0}")]
@@ -140,6 +137,7 @@ impl BedrockClient {
         max_tokens: i32,
         temperature: Option<f32>,
         cross_region_inference: bool,
+        user_query: Option<String>,
         diagnostic_logger: Option<Arc<BedrockDiagnosticLogger>>,
         messages_sent: Arc<Mutex<Vec<ConversationMessage>>>,
     ) -> Result<ResponseStream, BedrockError> {
@@ -226,16 +224,11 @@ impl BedrockClient {
             output,
             task_id.to_string(),
             needs_create_task,
+            user_query,
             diagnostic_logger,
             messages_sent,
+            effective_model_id,
         )))
     }
 
-    pub fn runtime_client(&self) -> &BedrockRuntimeClient {
-        &self.runtime_client
-    }
-
-    pub fn region(&self) -> &str {
-        &self.region
-    }
 }