Stage caching for batch runs, and an engine that lives in the command

A code node in a batch run is now fingerprinted by its source, its raw
settings and the values it reads — an artifact input counting as its digest,
which is what the content addressing was always for. A run that finds the key
restores what the earlier one returned and skips the node, recorded as
`cached`. The run history is the cache: `run_node.outputs` beside the
`cache_key` the schema already had, no second store. On for code nodes, never
for the built-in and connector types that have side effects; off per node with
`@node(cache=False)` and per run with `--no-cache`.

Emissions are not replayed on a hit, so a cached training node returns its
result without redrawing its curve. Recorded in NOTEPAD.md with the two other
deliberate limits.

`fluksio run --local` boots the real app in the command's own process and
drives it through its ASGI interface behind the ordinary client, so a run no
longer needs a `serve` terminal beside it — same data directory, same history,
and the cache carries between the two. It always waits, because the engine it
starts lives exactly as long as the command.

Also: `fluksio sweep --param lr=0.1,0.01` for the product of the lists,
`run --follow` for a run's numbers as they arrive, Ctrl-C cancelling a waited
run rather than abandoning it, coloured statuses on a terminal, and `name`
made optional on the metrics endpoint so a follower can ask for every series.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

frontend/src/client/schemas.gen.ts

@@ -1446,6 +1446,11 @@ export const MetricPointSchema = {
         value: {
             type: 'number',
             title: 'Value'
+        },
+        name: {
+            type: 'string',
+            title: 'Name',
+            default: ''
         }
     },
     type: 'object',
@@ -1628,6 +1633,12 @@ export const NodeDef_InputSchema = {
             title: 'Device Policy',
             description: 'What to do when no worker carries `device`: wait for one, or run locally anyway.',
             default: 'require'
+        },
+        cache: {
+            type: 'boolean',
+            title: 'Cache',
+            description: 'Whether a batch run may reuse an earlier execution of this node with the same source, settings and inputs. Turn it off for a function whose answer can change on its own.',
+            default: true
         }
     },
     type: 'object',
@@ -1717,6 +1728,12 @@ export const NodeDef_OutputSchema = {
             title: 'Device Policy',
             description: 'What to do when no worker carries `device`: wait for one, or run locally anyway.',
             default: 'require'
+        },
+        cache: {
+            type: 'boolean',
+            title: 'Cache',
+            description: 'Whether a batch run may reuse an earlier execution of this node with the same source, settings and inputs. Turn it off for a function whose answer can change on its own.',
+            default: true
         }
     },
     type: 'object',
@@ -2399,6 +2416,11 @@ export const RunCreateSchema = {
             type: 'boolean',
             title: 'Draft',
             default: false
+        },
+        no_cache: {
+            type: 'boolean',
+            title: 'No Cache',
+            default: false
         }
     },
     type: 'object',
@@ -2551,6 +2573,11 @@ export const RunNodeRowSchema = {
         logs: {
             type: 'string',
             title: 'Logs'
+        },
+        cache_key: {
+            type: 'string',
+            title: 'Cache Key',
+            default: ''
         }
     },
     type: 'object',
@@ -2781,6 +2808,11 @@ export const SweepCreateSchema = {
             type: 'boolean',
             title: 'Draft',
             default: false
+        },
+        no_cache: {
+            type: 'boolean',
+            title: 'No Cache',
+            default: false
         }
     },
     type: 'object',