feat: mount user repo as read-only with writable shannon overlay (#273)

* feat: mount user repo as read-only with deliverables bind-mount overlay

* feat: add playground and .playwright-cli overlay mounts

* feat: add filesystem context to pipeline-testing prompts

* fix: use explicit REPO_PATH in filesystem prompt for clarity

* fix: update filesystem prompts with playground notes and absolute screenshot paths

* feat: namespace writable overlays under .shannon/ to avoid polluting host repo

* refactor: rename playground to scratchpad

* fix: redirect playwright-cli output to writable .shannon/ overlay

* fix: pre-create .shannon/ overlay mount points for Linux compatibility

* fix: exclude nested node_modules and dist from Docker build context

* fix: enforce LF line endings for shell scripts on Windows

apps/worker/prompts/vuln-injection.txt

@@ -33,7 +33,7 @@ Success criterion: Complete source-to-sink traces detailing path, sanitizers, si
 </critical>
 
 <starting_context>
-- Your **single source of truth** for the application's structure is the reconnaissance report located at `deliverables/recon_deliverable.md`. You must derive your list of testable targets from this file.
+- Your **single source of truth** for the application's structure is the reconnaissance report located at `.shannon/deliverables/recon_deliverable.md`. You must derive your list of testable targets from this file.
 
 </starting_context>
 
@@ -42,8 +42,8 @@ Success criterion: Complete source-to-sink traces detailing path, sanitizers, si
 
 **Phase Sequence:** RECON (Complete) → **INJECTION ANALYSIS (You)** → EXPLOITATION (next phase)
 
-**Your Input:** `deliverables/recon_deliverable.md` (reconnaissance findings)
-**Your Output:** `deliverables/injection_analysis_deliverable.md` (analysis report for exploitation phase)
+**Your Input:** `.shannon/deliverables/recon_deliverable.md` (reconnaissance findings)
+**Your Output:** `.shannon/deliverables/injection_analysis_deliverable.md` (analysis report for exploitation phase)
 
 **WHAT HAPPENED BEFORE YOU:**
 - Reconnaissance agent mapped application architecture, attack surfaces, endpoints, input vectors
@@ -124,7 +124,7 @@ An **exploitable vulnerability** is a confirmed source-to-sink path where the en
 
   - **Goal:** Prove whether untrusted input can influence the **structure** of a backend command (SQL or Shell) or reach sensitive **slots** without the correct defense. No live exploitation in this phase.
   - **1) Create a To Do for each Injection Source found in the Pre-Recon Deliverable
-		  - inside of deliverables/pre_recon_deliverable.md under the section "7. Injection Sources (Command Injection and SQL Injection)" use the TodoWrite tool to create a task for each discovered Injection Source. 
+		  - inside of .shannon/deliverables/pre_recon_deliverable.md under the section "7. Injection Sources (Command Injection and SQL Injection)" use the TodoWrite tool to create a task for each discovered Injection Source. 
 		  - Note: All sources are marked as Tainted until they Hit a Santiization that matches the sink context. normalizers (lowercasing, trimming, JSON parse, schema decode) — still **tainted**.
     - **2) Trace Data Flow Paths from Source to Sink**
 		    - For each source, your goal is to identify every unique "Data Flow Path" to a database sink. A path is a distinct route the data takes through the code.
@@ -148,7 +148,7 @@ An **exploitable vulnerability** is a confirmed source-to-sink path where the en
     - If concat occurred **after** sanitization, treat that sanitization as **non-effective** for this path.
   - **6) Append to findings list (consistent fields)**
 	  -  **If the verdict is `vulnerable`:** Include the finding in your exploitation queue. Set `externally_exploitable` to `true` ONLY if exploitable via public internet without internal access. Ensure all fields in the `exploitation_queue_format`, including a minimal `witness_payload`, are populated.
-    - **If the verdict is `safe`:** DO NOT add the finding to the exploitation queue. These secure vectors must be documented later in the "Vectors Analyzed and Confirmed Secure" section of your final Markdown report (`deliverables/injection_analysis_deliverable.md`).
+    - **If the verdict is `safe`:** DO NOT add the finding to the exploitation queue. These secure vectors must be documented later in the "Vectors Analyzed and Confirmed Secure" section of your final Markdown report (`.shannon/deliverables/injection_analysis_deliverable.md`).
     - **If a single source is found to be vulnerable via multiple, distinct paths to different sinks, you must create a separate vulnerability entry in the exploitation queue for each unique vulnerable path.**
     - **QUEUE INCLUSION CRITERIA:** ONLY include vulnerabilities where `externally_exploitable = true`. Exclude any vulnerability requiring internal network access, VPN, or direct server access.
 
@@ -287,7 +287,7 @@ When you have systematically analyzed all input vectors, you MUST generate two f
 
 **1. Your Specialist Deliverable**
 
-First, synthesize all of your findings into a single, detailed Markdown report located at `deliverables/injection_analysis_deliverable.md`. This report is the official record of your work.
+First, synthesize all of your findings into a single, detailed Markdown report located at `.shannon/deliverables/injection_analysis_deliverable.md`. This report is the official record of your work.
 
 Your report MUST use the following structure precisely:
 
@@ -352,10 +352,10 @@ These input vectors were traced and confirmed to have robust, context-appropriat
 1. **Todo Completion:** ALL tasks in your TodoWrite list must be marked as "completed"
 2. **Deliverable Generation:** Your deliverable must be successfully saved using the save-deliverable CLI tool:
    - **CHUNKED WRITING (MANDATORY):**
-     1. Use the **Write** tool to create `deliverables/injection_analysis_deliverable.md` with the title and first major section
+     1. Use the **Write** tool to create `.shannon/deliverables/injection_analysis_deliverable.md` with the title and first major section
      2. Use the **Edit** tool to append each remaining section — match the last few lines of the file, then replace with those lines plus the new section content
      3. Repeat step 2 for all remaining sections
-     4. Run `save-deliverable` with `--type INJECTION_ANALYSIS --file-path "deliverables/injection_analysis_deliverable.md"`
+     4. Run `save-deliverable` with `--type INJECTION_ANALYSIS --file-path ".shannon/deliverables/injection_analysis_deliverable.md"`
      **WARNING:** Do NOT write the entire report in a single tool call — exceeds 32K output token limit. Split into multiple Write/Edit operations.
 
 **Note:** Save your deliverable markdown via save-deliverable first. The exploitation queue is captured automatically at the end of your session.