This commit addresses 6 critical issues identified during code review,
plus build improvements for better user experience.

Critical fixes:
- Issue #1: PID file race condition - kill router process if PID file
  write fails to prevent untrackable processes
- Issue #2: Cross-platform compatibility - replace hardcoded /tmp paths
  with os.TempDir() and add user-specific suffixes using os.Getuid()
- Issue #3: Signal handling - add graceful shutdown for port-forward
  process on Ctrl+C to prevent orphaned kubectl processes
- Issue #4: HTTP timeout - add 30-second timeout to prevent hanging
  requests in test command
- Issue #5: Security - restrict log/PID file permissions to 0600
- Issue #6: Input validation - enforce 10k character limit on prompts

Build improvements:
- Embed library path using -ldflags="-r" to eliminate need for users
  to manually set LD_LIBRARY_PATH when running vsr binary

Files modified:
- src/semantic-router/pkg/cli/deployment/deployment.go
- src/semantic-router/pkg/cli/deployment/upgrade.go
- src/semantic-router/cmd/vsr/commands/dashboard.go
- src/semantic-router/cmd/vsr/commands/test.go
- tools/make/build-run-test.mk
- src/semantic-router/pkg/cli/deployment/deployment_test.go

All fixes have been verified with standalone test programs.

Signed-off-by: Srinivas A <56465971+srini-abhiram@users.noreply.github.com>

This commit addresses 6 critical issues identified during code review,
plus build improvements for better user experience.

Critical fixes:
- Issue #1: PID file race condition - kill router process if PID file
  write fails to prevent untrackable processes
- Issue #2: Cross-platform compatibility - replace hardcoded /tmp paths
  with os.TempDir() and add user-specific suffixes using os.Getuid()
- Issue #3: Signal handling - add graceful shutdown for port-forward
  process on Ctrl+C to prevent orphaned kubectl processes
- Issue #4: HTTP timeout - add 30-second timeout to prevent hanging
  requests in test command
- Issue #5: Security - restrict log/PID file permissions to 0600
- Issue #6: Input validation - enforce 10k character limit on prompts

Build improvements:
- Embed library path using -ldflags="-r" to eliminate need for users
  to manually set LD_LIBRARY_PATH when running vsr binary

Files modified:
- src/semantic-router/pkg/cli/deployment/deployment.go
- src/semantic-router/pkg/cli/deployment/upgrade.go
- src/semantic-router/cmd/vsr/commands/dashboard.go
- src/semantic-router/cmd/vsr/commands/test.go
- tools/make/build-run-test.mk
- src/semantic-router/pkg/cli/deployment/deployment_test.go

All fixes have been verified with standalone test programs.

Signed-off-by: Srinivas A <56465971+srini-abhiram@users.noreply.github.com>

Add unit tests to verify all 6 critical production fixes implemented
in the previous commit. Tests ensure cross-platform compatibility,
security, and robustness of the VSR CLI tool.

Test coverage added:
- Cross-platform path handling (Issue #2)
  * Absolute path validation
  * User-specific path generation
  * Temp directory usage

- PID file management and security (Issues #1, #5)
  * PID file race condition handling
  * Process termination on write failure
  * Restrictive 0600 file permissions
  * Proper cleanup on exit

- HTTP client timeout (Issue #4)
  * 30-second timeout prevents hanging
  * Fast responses unaffected
  * Timeout configuration validation

- Input validation (Issue #6)
  * 10k character limit enforcement
  * Boundary condition testing

- Signal handling (Issue #3)
  * Graceful shutdown on interrupt
  * Process cleanup verification
  * No orphaned processes

All tests compile and validate the production fixes.

Signed-off-by: Srinivas A <56465971+srini-abhiram@users.noreply.github.com>