Remove non-functional @mention resolution patch

The @mention patch fetched /prompts/users via the legacy client, which returns
Unauthorized at runtime (verified against live API) — it never resolved a mention,
silently posting literal @name text with a stderr warning. Restore the six touched
files to upstream state, drop mentions.go/mentions_test.go, and remove the stale
skill reference. The fork is now docs-only on top of upstream.

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

Author: waynemsmith

internal/client/client.go

@@ -170,49 +170,6 @@ func (c *Client) Delete(path string) (*APIResponse, error) {
 	return c.request("DELETE", path, nil)
 }
 
-// GetHTML performs a GET request expecting an HTML response.
-// Unlike Get, it sets Accept: text/html and does not attempt JSON parsing.
-func (c *Client) GetHTML(path string) (*APIResponse, error) {
-	requestURL := c.buildURL(path)
-	req, err := http.NewRequestWithContext(context.Background(), "GET", requestURL, nil)
-	if err != nil {
-		return nil, errors.NewNetworkError(fmt.Sprintf("Failed to create request: %v", err))
-	}
-
-	c.setHeaders(req)
-	req.Header.Set("Accept", "text/html")
-
-	if c.Verbose {
-		fmt.Fprintf(os.Stderr, "> GET %s (HTML)\n", requestURL)
-	}
-
-	resp, err := c.doWithRetry(req)
-	if err != nil {
-		return nil, errors.NewNetworkError(fmt.Sprintf("Request failed: %v", err))
-	}
-	defer func() { _ = resp.Body.Close() }()
-
-	respBody, err := io.ReadAll(resp.Body)
-	if err != nil {
-		return nil, errors.NewNetworkError(fmt.Sprintf("Failed to read response: %v", err))
-	}
-
-	if c.Verbose {
-		fmt.Fprintf(os.Stderr, "< %d %s\n", resp.StatusCode, http.StatusText(resp.StatusCode))
-	}
-
-	apiResp := &APIResponse{
-		StatusCode: resp.StatusCode,
-		Body:       respBody,
-	}
-
-	if resp.StatusCode >= 400 {
-		return apiResp, c.errorFromResponse(resp.StatusCode, respBody, resp.Header)
-	}
-
-	return apiResp, nil
-}
-
 func (c *Client) request(method, path string, body any) (*APIResponse, error) {
 	requestURL := c.buildURL(path)
 

internal/client/interface.go

@@ -13,7 +13,6 @@ type API interface {
 	FollowLocation(location string) (*APIResponse, error)
 	UploadFile(filePath string) (*APIResponse, error)
 	DownloadFile(urlPath string, destPath string) error
-	GetHTML(path string) (*APIResponse, error)
 }
 
 // Ensure Client implements API interface

internal/commands/card.go

@@ -240,7 +240,7 @@ var cardCreateCmd = &cobra.Command{
 			return newRequiredFlagError("title")
 		}
 
-		description, err := resolveRichTextContent(cardCreateDescription, cardCreateDescriptionFile, getClient())
+		description, err := resolveRichTextContent(cardCreateDescription, cardCreateDescriptionFile)
 		if err != nil {
 			return err
 		}
@@ -330,7 +330,7 @@ var cardUpdateCmd = &cobra.Command{
 		cardNumber := args[0]
 
 		hasDescriptionInput := cardUpdateDescription != "" || cardUpdateDescriptionFile != ""
-		description, err := resolveRichTextContent(cardUpdateDescription, cardUpdateDescriptionFile, getClient())
+		description, err := resolveRichTextContent(cardUpdateDescription, cardUpdateDescriptionFile)
 		if err != nil {
 			return err
 		}

internal/commands/comment.go

@@ -142,7 +142,7 @@ var commentCreateCmd = &cobra.Command{
 			return newRequiredFlagError("card")
 		}
 
-		body, err := resolveRichTextContent(commentCreateBody, commentCreateBodyFile, getClient())
+		body, err := resolveRichTextContent(commentCreateBody, commentCreateBodyFile)
 		if err != nil {
 			return err
 		}
@@ -206,7 +206,7 @@ var commentUpdateCmd = &cobra.Command{
 		cardNumber := commentUpdateCard
 
 		hasBodyInput := commentUpdateBody != "" || commentUpdateBodyFile != ""
-		body, err := resolveRichTextContent(commentUpdateBody, commentUpdateBodyFile, getClient())
+		body, err := resolveRichTextContent(commentUpdateBody, commentUpdateBodyFile)
 		if err != nil {
 			return err
 		}

internal/commands/inline_attachments.go

@@ -6,26 +6,21 @@ import (
 	"os"
 	"strings"
 
-	"github.com/basecamp/fizzy-cli/internal/client"
 	"github.com/basecamp/fizzy-cli/internal/errors"
 )
 
-// resolveRichTextContent reads body content (inline or from a file), resolves
-// @Name mentions to ActionText mention attachments using c, then converts the
-// result from markdown to HTML. Mentions are resolved before HTML conversion so
-// the inserted attachment markup passes through goldmark unchanged.
-func resolveRichTextContent(content string, filePath string, c client.API) (string, error) {
+func resolveRichTextContent(content string, filePath string) (string, error) {
 	if filePath != "" {
 		fileContent, err := os.ReadFile(filePath)
 		if err != nil {
 			return "", err
 		}
-		return markdownToHTML(resolveMentions(string(fileContent), c)), nil
+		return markdownToHTML(string(fileContent)), nil
 	}
 	if content == "" {
 		return "", nil
 	}
-	return markdownToHTML(resolveMentions(content, c)), nil
+	return markdownToHTML(content), nil
 }
 
 func appendInlineAttachmentsToContent(content string, paths []string) (string, error) {