Rename Project Memory to Workspace Memory

Rename all references from "Project Memory" to "Workspace Memory" to avoid
future conflation if a "project" concept is introduced later.

Changes:
- Rename read_project_memory() -> read_workspace_memory()
- Update all prompts, tool descriptions, and comments
- Update header parsing in memory.rs to use "# Workspace Memory"
- Update display detection for "=== Workspace Memory ==="
- Update documentation and analysis/memory.md

11 files changed, ~36 occurrences updated.

crates/g3-core/src/tools/mod.rs

@@ -8,7 +8,7 @@
 //! - `webdriver` - Browser automation via WebDriver
 //! - `misc` - Other tools (screenshots, code search, etc.)
 //! - `research` - Web research via scout agent
-//! - `memory` - Project memory (read_memory, remember)
+//! - `memory` - Workspace memory (remember)
 //! - `acd` - Aggressive Context Dehydration (rehydrate)
 
 pub mod executor;