Track Rust workspace; fix .gitignore and ambiguous cargo target

Bring the toolwall Rust workspace under version control and fix the build.

The root .gitignore was a 3,497-line multi-template mashup whose Jenkins
section contained a blanket `/*` rule that silently ignored the entire repo
root — so all crates, Cargo.toml, examples, the justfile and docs were never
tracked.

- Replace .gitignore with a focused Rust/Cargo ignore.
- Remove a stray empty nested git repo under crates/toolwall-scan/.
- Make cargo target selection explicit: CLI binary is now named `toolwall`
  (default-run + autobins=false), fixing "More than one artifact was produced".
- Add a justfile with explicit run/build/check/test/lint targets.
- Update README; deslop restating comments; ignore per-user .idea state.

Validated: cargo check/test/clippy --workspace all pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: mcaney006

.gitignore

@@ -0,0 +1,17 @@
+# Rust / Cargo
+/target/
+**/*.rs.bk
+*.pdb
+
+# Python dev tooling (black formatter env declared in pyproject.toml)
+/.venv/
+__pycache__/
+*.py[cod]
+
+# Local agent / session state — not part of the project
+/.remember/
+/.ai/
+
+# OS & editor noise
+.DS_Store
+*.swp

.idea/.gitignore

@@ -0,0 +1,16 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All Tests" type="CargoCommandRunConfiguration" factoryName="Cargo Command">
+    <option name="command" value="test --workspace" />
+    <option name="workingDirectory" value="file://$PROJECT_DIR$" />
+    <envs />
+    <option name="channel" value="DEFAULT" />
+    <option name="requiredFeatures" value="true" />
+    <option name="allFeatures" value="false" />
+    <option name="withSudo" value="false" />
+    <option name="buildProfileId" value="test" />
+    <option name="backtrace" value="SHORT" />
+    <method v="2">
+      <option name="CARGO.BUILD_TASK_PROVIDER" enabled="true" />
+    </method>
+  </configuration>
+</component>

.idea/amazonq.xml

@@ -0,0 +1,17 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Run toolwall-cli" type="CargoCommandRunConfiguration" factoryName="Cargo Command">
+    <option name="command" value="run --package toolwall-cli --bin toolwall" />
+    <option name="workingDirectory" value="file://$PROJECT_DIR$" />
+    <envs />
+    <option name="emulateTerminal" value="true" />
+    <option name="channel" value="DEFAULT" />
+    <option name="requiredFeatures" value="true" />
+    <option name="allFeatures" value="false" />
+    <option name="withSudo" value="false" />
+    <option name="buildProfileId" value="dev" />
+    <option name="backtrace" value="SHORT" />
+    <method v="2">
+      <option name="CARGO.BUILD_TASK_PROVIDER" enabled="true" />
+    </method>
+  </configuration>
+</component>