chore(cli): remove unused v0.0 scaffolding

Foundation PR-1 reserved several internal packages and helpers as
scaffolding for follow-up PRs that ended up taking different routes.
Audit confirms zero production references; this commit removes them so
the cli/ tree reflects what's actually shipped.

Removed (148 LOC):

  cli/internal/safepaths/                 — `Validate` / `WithinRoot` /
                                            three sentinel errors. Reserved
                                            for `weknora doc upload`'s path
                                            scrubbing; that command landed
                                            in PR-10 using its own
                                            `validateUploadPath` (os.Stat +
                                            regular-file check) — sufficient
                                            for the actual threat model
                                            (local CLI invocations).

  cli/internal/cmdutil/json_flags.go      — `AddJSONFlags` helper +
                                            unused --jq / --template flag
                                            registration. Reserved for PR-3
                                            "lipgloss tables / jq evaluator"
                                            which never materialized; every
                                            command directly registers
                                            BoolVar(&JSONOut, "json", ...)
                                            since v0.0 ship time.

  cmdutil.NewTableExporter                — empty alias for jsonExporter,
                                            reserved for the same PR-3
                                            renderer. Removed; jsonExporter
                                            stays under NewJSONExporter.

  cmdutil.Options marker interface        — empty interface{} reserved as a
                                            convention; no command embeds
                                            or asserts against it.

Stale comments fixed:

  - cmd/root.go: package comment updated kb (list+get) → kb
    (list+view+create+delete) and noted the `get` cobra alias.
  - cmd/root.go: dropped --no-version-check forward-reference (no such flag).
  - cmd/root.go: removed "(PR-7)" attribution from NewRootCmd doc comment.
  - cmd/kb/kb.go: same package-comment update.
  - cmd/chat/chat.go: replaced "PR-7" mention in --help example with a
    generic placeholder so cobra-rendered help is review-clean.
  - cmd/search/search.go: removed "Lipgloss tables arrive in PR-3"
    forward-reference; the inline indent helper is the shipped form.
  - internal/agent/annotations.go: ShouldUseAgentMode → DetectAIAgent
    (removed in PR-12).

AGENTS.md "Known limitations" section added:
  Documents that chat / search / doc upload currently surface server-side
  precondition misses (LLM / vector store / storage engine not configured)
  as `network.error` with `context deadline exceeded`. A planned future
  release will introduce a `precondition.*` typed error namespace
  (server returns HTTP 412 before opening the SSE / streaming response).
  This documents the limitation honestly for reviewers and integrators
  rather than claiming a behavior we don't yet have.

Tests: 27 cli packages pass (safepaths_test was the 28th — gone with the
package). go vet clean.

cli/cmd/chat/chat.go

@@ -78,7 +78,7 @@ Modes:
   TTY (default):              live token streaming + reference footer
   Pipe / --no-stream / --json: buffered, emitted once on completion`,
 		Example: `  weknora chat "What is RRF?" --kb-id kb_123
-  weknora chat "Summarise PR-7" --kb my-kb --json
+  weknora chat "Summarise this design doc" --kb my-kb --json
   weknora chat "Continue?" --session-id sess_abc`,
 		Args: cobra.MinimumNArgs(1),
 		RunE: func(c *cobra.Command, args []string) error {

cli/cmd/kb/kb.go

@@ -1,4 +1,6 @@
-// Package kb holds `weknora kb` command tree (list / get; create / delete in v0.2).
+// Package kb holds the `weknora kb` command tree: list / view / create / delete.
+// `view` is the primary read verb (gh repo view convention); `get` survives as
+// a cobra alias on the view subcommand for v0.0/v0.1 callers.
 package kb
 
 import (

cli/cmd/root.go

@@ -134,7 +134,7 @@ var cobraFlagErrorPrefixes = []string{
 }
 
 // NewRootCmd builds the cobra tree. Splitting it from Execute() lets tests
-// drive the tree directly with their own factory. Exported (PR-7) so the
+// drive the tree directly with their own factory. Exported so the
 // acceptance/contract suite can construct the tree in-process.
 func NewRootCmd(f *cmdutil.Factory) *cobra.Command {
 	v, commit, date := build.Info()
@@ -192,9 +192,6 @@ hybrid searches against a WeKnora server from your shell or an AI agent.`,
 // addGlobalFlags registers persistent flags available on every subcommand.
 // Only flags whose behavior is actually wired are listed — a flag that
 // accepts values but does nothing is a worse contract than no flag.
-//
-// --context lands here in v0.1 (spec §1.2); --no-version-check waits for
-// v0.7's compat probe consumer.
 func addGlobalFlags(cmd *cobra.Command) {
 	pf := cmd.PersistentFlags()
 	pf.BoolP("yes", "y", false, "Skip confirmation prompts on destructive operations")

cli/cmd/search/search.go

@@ -133,10 +133,9 @@ func runSearch(ctx context.Context, opts *Options, svc Service) error {
 	return renderHumanResults(results, opts.KBID)
 }
 
-// renderHumanResults prints a compact pretty list to stdout.
-//
-// Lipgloss tables arrive in PR-3; the inline indent helper here is a minimal
-// stopgap so search is usable in a terminal without color today.
+// renderHumanResults prints a compact pretty list to stdout. The inline
+// indent helper is a minimal stopgap so search output is usable in a plain
+// terminal; a richer tabular renderer can replace this later.
 func renderHumanResults(results []*sdk.SearchResult, kbID string) error {
 	if len(results) == 0 {
 		fmt.Fprintln(iostreams.IO.Out, "(no results)")