feat(agent): guide agents to report missing guidance when grep finds no matches (#1860)

## Summary
- When `speakeasy agent context --grep` returns no results, the error
message now includes instructions for submitting feedback about missing
documentation
- Added `missing_guidance` feedback type (stored in metadata) for
tracking documentation gaps
- This helps agents track and report gaps in the agent context docs when
they search for something that doesn't exist

## Example

Before:
```
$ speakeasy agent context --grep "bumpMajor"
Error: Exit code 1
no matches found for: bumpMajor
```

After:
```
$ speakeasy agent context --grep "bumpMajor"
no matches found for: bumpMajor

This may indicate missing guidance in the agent context documentation.
Please submit feedback so we can improve the docs:

  speakeasy agent feedback --type missing_guidance --message "Searched for 'bumpMajor' but found no results. Context: <describe what you were trying to accomplish>"

Your feedback helps us identify gaps in the documentation.
```

## Test plan
- [x] Build passes
- [x] Unit tests pass
- [x] Manually tested grep with no matches shows new message
- [x] Verified feedback help shows new `missing_guidance` type

Author: vishalg0wda

cmd/agent.go

@@ -145,7 +145,7 @@ var agentFeedbackCmd = &model.ExecutableCommand[AgentFeedbackFlags]{
 		flag.StringFlag{
 			Name:         "type",
 			Shorthand:    "t",
-			Description:  "Feedback type: agent_context or general",
+			Description:  "Feedback type: agent_context, missing_guidance, or general",
 			DefaultValue: "agent_context",
 		},
 		flag.StringFlag{

internal/agent/context.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io/fs"
+	"os"
 	"path"
 	"regexp"
 	"sort"
@@ -460,6 +461,14 @@ func Grep(contentFS fs.FS, opts GrepOptions) error {
 	}
 
 	if len(allMatches) == 0 {
+		fmt.Fprintf(os.Stderr, `This may indicate missing guidance in the agent context documentation.
+Please submit feedback so we can improve the docs:
+
+  speakeasy agent feedback --type missing_guidance --message "Searched for '%s' but found no results. Context: <describe what you were trying to accomplish>"
+
+Your feedback helps us identify gaps in the documentation.
+
+`, opts.Pattern)
 		return fmt.Errorf("no matches found for: %s", opts.Pattern)
 	}
 

internal/agent/feedback.go

@@ -25,6 +25,9 @@ func SubmitFeedback(ctx context.Context, feedbackType, message, contextPath stri
 	}
 
 	metadata := map[string]any{}
+	if feedbackType == "missing_guidance" {
+		metadata["feedback_subtype"] = "missing_guidance"
+	}
 	if contextPath != "" {
 		metadata["context_path"] = contextPath
 	}